Simple headlamp relay with start cutout

[posplayr]

Here is a simple way to add a Headlamp relay and get Headlamp cutout during start.

I have not tested it but seems clear it will work as long as the relay you add has a much higher resistance than the OEM starter solenoid relay. The OEM specs out at 3-4 ohms and a typical Bosch relay is closer to 75 ohms

[rustybronco]

Why not power a N.C relay off the switched side of the ignition with power the H.I.D. and pull it open off the start circuit?

[posplayr]

Why not power a N.C relay off the switched side of the ignition with power the H.I.D. and pull it open off the start circuit?

At least define the connections if not provide a schematic.

From you description it doesn't appear to match the truth table.

Is it any less parts?

[rustybronco]

At least define the connections if not provide a schematic.

Is it any less parts?

No less parts. It just doesn't introduce anything between B+ and the ignition switch.

Switched pwr> 30

HID> 87? 87A? (whichever is N.C.)

GND>85

Start button> 86

[duaneage]

an easier solution is to use a diode off one leg of the stator to power a relay. This has the added benefit of being used in production on several makes and models of bikes currently.
I hooked mine up that way, followed the wiring diagram of a yamaha I had.

[rustybronco]

Nice solution Mr. Duaneage.

[posplayr]

an easier solution is to use a diode off one leg of the stator to power a relay. This has the added benefit of being used in production on several makes and models of bikes currently.
I hooked mine up that way, followed the wiring diagram of a yamaha I had.

Not sure what that does, as soon as the engine starts to crank the alternator produces power. If the relay coil sized to require a running engine to get the headlamp on? How do you turn the headlamp off? Break the ground side of the same relay?

I have heard of such, but it would appear to do the same think except you had to add an additional diode as well as a ground wire to rewire a headlamp switch for on/off.

While sensing the stator for a running engine is an interesting technique, I'm not sure it is an easier implementation of a headlamp relay with cutout.

That being said it does something new keeps the lights off until the bike is running.if you have a shunt r/r you might get away with just a diode. You probably need a little more with a series r/r.

[tkent02]

One thing to think about with all of these ideas, if relay or something goes up in smoke will the headlight stay on?

Suddenly going dark at speed on a winding mountain road is not fun. Been there, don't want to do it again.

[duaneage]

Hook the yellow to any stator lead, I used one of those wires that used to go the the handle bar switch ( it stills does ) and I got a relay from a Yamaha 400 that did the same thing on the 400 special. The fun thing is the light stays on for a bit after the engine stops until the charge goes down. you could use a bosch if you wanted too.
I got a diode from radio shack for a dollar for the charge pump. you can have all the lights stay off until the bike starts, handy for kick starting or just neato to watch it all come to life when the engine does.

I should make up a kit and call it Solid State Headlight Actuator and charge about a 150 dollars for it.

[posplayr]

One thing to think about with all of these ideas, if relay or something goes up in smoke will the headlight stay on?

Suddenly going dark at speed on a winding mountain road is not fun. Been there, don't want to do it again.

Tom,

That is certainly a consideration, but also not a new one.
The use of a relay to power even a safety critical device such as a headlamp has been done for years on cars and certainly adds no additional concern for a motorcycle unless mounted in an area where excessive heat and vibration will cause the relay to fail even sooner that the accepted failure rates.

Using a solid state relay has benefits in that there is much less tendency to fail due to the same temperature ad vibration environments. With heavier electrical loads, more current switching devices are typically needed and the space saving coupled with enhanced reliability tip the balance toward solid state on more modern system.

If the device is FET based vs (SCR or Bipolar device)based, the likelihood is 10:1 that the FET will fail in the ON position so running you battery down is the biggest issue for a failed solid state headlamp relay.

Jim

[duaneage]

"If the device is FET based vs (SCR or Bipolar device)based, the likelihood is 10:1 that the FET will fail in the ON position so running you battery down is the biggest issue for a failed solid state headlamp relay."

Or you could just turn the key off and not run the battery down.

1 diode = 1.00
1 relay = 3.95
bit o connectors and wire = 5.00

Simple solution.

[posplayr]

No less parts. It just doesn't introduce anything between B+ and the ignition switch.

Switched pwr> 30

HID> 87? 87A? (whichever is N.C.)

GND>85

Start button> 86

The point of the relay is to reduce voltage losses between the battery and the fuse box (the second time) where the full 11 amps causes the biggest voltage drops.

The incandescent lights pull just as much if not more current than the headlamp so this is one of the biggest voltage drops for the Headlamp circuit.

OEM:
BAT==>MAIN FUSE==>R==>IGN=>O==>HEADLAMP FUSE=>O/R

Simple Mod:
BAT==>IN LINE FUSE==>RELAY==>O/R

Yours still runs all the headlamp current through the IGN switch.

BAT==>MAIN FUSE==>R==>IGN==>O==>RELAY==>O/R

[rustybronco]

No, the point of the relay was to de-power the headlight circuit while cranking.

Yes, the way I have shown it draws power off the ignition switch for the headlights, just like they factory did. One could easily power the relay using a connection to the coil mod (if used) or in the event of a voltage drop coming off the ignition switch, while utilizing the factory wiring and (or) tapped at the fuse box (if used),one could just as easily correct any wiring loom defects bringing the voltage back to where it should be.

[posplayr]

No, the point of the relay was to de-power the headlight circuit while cranking.

Yes, the way I have shown it draws power off the ignition switch for the headlights, just like they factory did. One could easily power the relay using a connection to the coil mod (if used) or in the event of a voltage drop coming off the ignition switch, while utilizing the factory wiring and (or) tapped at the fuse box (if used),one could just as easily correct any wiring loom defects bringing the voltage back to where it should be.

I think you mistook my intent.

HEADLAMP RELAY and START CUTOUT. HEADLAMP RELAY implies pin 30 is connected to unswitched power.

The purpose of the thread twas to discuss the solution to the problem Bwanna is working on. Removing a control relay to control his HID relay. This provides the function only one relay. Duaneage's would also meet that requirement of a single relay although it has the single extra diode assuming it doesn't have issues with Series R/R..

http://www.thegsresources.com/_forum/showpost.php?p=2011715&postcount=34

Not a head lamp relay in order to do a headlamp cut out.

[posplayr]

"If the device is FET based vs (SCR or Bipolar device)based, the likelihood is 10:1 that the FET will fail in the ON position so running you battery down is the biggest issue for a failed solid state headlamp relay."

Or you could just turn the key off and not run the battery down.

1 diode = 1.00
1 relay = 3.95
bit o connectors and wire = 5.00

Simple solution.

If the FET's are powered from the battery there is no switch to turn off.

Also your solution is quite applicable to the original problem.